AN IMPORTANT ASPECT OF SDI DEVELOPMENT OF X-RAY LASER (XRL) WEAPONS SYSTEMS AND THE COUNTERMEASURES IS THE EXPERIMENTAL VALIDATION OF EFFECTS OF SIMULATION FIDELITY AND THE CREATION OF MATERIALS RESPONSE DATABASES. THIS EXPERIMENTALPROGRAM USES AS A SOURCE OF INTENSE SOFT X-RAY THE PLASMA RADIATING SOURCE (PRS) OPERATED BY THE DEFENSE NUCLEAR AGENCY. THE PRS AS CURRENTLY USED FALLS TO PROVIDE SUFFICIENT X-RAY FLUENCE, SPECTRAL QUALITY AND DEBRIS-FREE MEASUREMENT ENVIRONMENT REQUIRED BY THIS NEW XRL EFFECTS TESTING ROLE. A CALCULATIONAL/EXPERIMENTAL PHASE I PROJECT IS PROPOSED TO DEVELOP A SPECTRALLY DISCRIMINATING X-RAY CONCENTRATOR OPTIC COMPONENT THAT WILL IMPROVE PRS PERFORMANCE IN THE XRL TESTING ROLE. THE BASIS FOR THIS COM PONENT IS THE ADVANCED LAYERED SYNTHETIC MICROSTRUCTURE (LSM) X-RAY INTERFERENCE MIRROR. PHASE I CALCULATIONAL EFFORT WILL ESTABLISH THE FEASIBILITY OF CONSTRUCTING FIGURED LSM X-RAY CONCENTRATOR OPTICS OFR PRS ENHANCEMENT. EXPERIMENTS WILL BE CONDUCTED AT A PRS FACILITY TO DEMONSTRATE DEBRIS MITIGATION AND TO INVESTIGATE LSM SURVIVABILITY IN THE PRS ENVIRONMENT.